Thyroid UK
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Help for blood test tomorrow

Hi all those of you who are so helpful.

Having bloods at docs tomorrow at 8.30am I know not to take T4. I take t4 -and 12.5 T3 in the early hours of the morning.

However I take 12.5 T3 when I go to bed at about 10.30pm.

Now the question is, can I take the 10.30pm dose of T3 or no.

Thanks in advance for any help 🤔🙂

Having had TT in February it has been a slow learning curve, but thanks to this forum I am slowly getting there, if think x

4 Replies

I'd miss the late T3 dose but you can add it to your morning dose as well, after the blood test and then carry on as usual.


You should leave 12 hours between T3 and the test. So, if you skip your evening dose, you will be leaving aout 36 hours between the test and the last dose, and that's much too long. Can you not take your T3 a little earlier the evening before the test, so as to make it a 12 hour gap?


I think knowing when to take your T3 creates a dilemma. Some say it peaks at two hours, or four hours or six hours. I have no idea but remember, this whole timing business was to get to see your highest TSH level so that doctors will not reduce your dose. That is still a good plan for T4 but realistically, I'd like to see where my FT3 is really at and not manipulate the outcome. Personally I would probably take that evening dose at the normal time. I have never read anything more definitive and I'm not a professional.


Thanks guys. I am grateful for your advice 🙂 Might post results when I get them for more info. X


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